Self-defining memories: last episodic memories bastion in normal aging?

Autobiographical memory is constituted by different representations including general knowledge about one's past (semantic component) and specific personal events (episodic component). Some old memories can remain very vivid because they are particularly important for the subject's identity. The aim of this paper is, in the first part, to present a review of the properties of these memories, called self-defining memories, which present episodic characteristics and are closely related to personal semantics and subject's identity model. In the second part, we analyse the results of a preliminary study designed to assess the effect of age on self-defining memories compared to episodic and semantic memories. The results show that the elderly subjects' performance is impaired during the retrieval of episodic memories, while no difference was found between young and older group for retrieving semantic and self-defining memories. However, self-defining memories were predominantly constituted of episodic characteristics in the two age groups. In spite of their episodic nature, their close relationship to the subject's identity model enables to maintain an efficient access to most specific details of memories in normal aging. These results could contribute to improve autobiographical memory rehabilitation in old patients with depression and Alzheimer's disease who suffer from overgeneralization of memories.